package com.offroader.view;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;

import com.offroader.R;

public class MySlidButton extends View implements OnTouchListener {

	private boolean nowChoose = false;// 记录当前按钮是否打开，true为打开，false为关闭  
	private boolean onSlip = false;// 记录用户是否在滑动  
	private float downX, nowX; // 按下时的x，当前的x  
	private Rect btn_on, btn_off;// 打开和关闭状态下，游标的Rect  

	private boolean isChgLsnOn = false;//是否设置监听  
	private OnChangedListener changedLis;

	private Bitmap bg_on, bg_off, slip_btn;

	public MySlidButton(Context context, AttributeSet attrs) {
		super(context, attrs);
		init();
	}

	public MySlidButton(Context context) {
		super(context);
		init();
	}

	private void init() {
		// 载入图片资源  
		bg_on = BitmapFactory.decodeResource(getResources(), R.drawable.ic_switch_on);
		bg_off = BitmapFactory.decodeResource(getResources(), R.drawable.ic_switch_off);
		slip_btn = BitmapFactory.decodeResource(getResources(), R.drawable.ic_switch_btn);
		// 获得需要的Rect数据  
		btn_on = new Rect(0, 0, slip_btn.getWidth(), slip_btn.getHeight());
		btn_off = new Rect(bg_off.getWidth() - slip_btn.getWidth(), 0, bg_off.getWidth(), slip_btn.getHeight());
		setOnTouchListener(this);
	}

	@Override
	protected void onDraw(Canvas canvas) {
		// TODO Auto-generated method stub  
		super.onDraw(canvas);

		Matrix matrix = new Matrix();
		Paint paint = new Paint();
		float x;

		{
			if (nowX < (bg_on.getWidth() / 2)) //滑动到前半段与后半段的背景不同,在此做判断  
				canvas.drawBitmap(bg_off, matrix, paint);//画出关闭时的背景  
			else
				canvas.drawBitmap(bg_on, matrix, paint);//画出打开时的背景   

			if (onSlip) {//是否是在滑动状态,    
				if (nowX >= bg_on.getWidth())//是否划出指定范围,不能让游标跑到外头,必须做这个判断  
					x = bg_on.getWidth() - slip_btn.getWidth() / 2;//减去游标1/2的长度  
				else
					x = nowX - slip_btn.getWidth() / 2;
			} else {
				if (nowChoose)//根据现在的开关状态设置画游标的位置   
					x = btn_off.left;
				else
					x = btn_on.left;
			}

			if (x < 0) //对游标位置进行异常判断..  
				x = 0;
			else if (x > bg_on.getWidth() - slip_btn.getWidth())
				x = bg_on.getWidth() - slip_btn.getWidth();

			canvas.drawBitmap(slip_btn, x, 0, paint);//画出游标.     
		}
	}

	@Override
	public boolean onTouch(View v, MotionEvent event) {

		switch (event.getAction()) {//根据动作来执行代码  

		case MotionEvent.ACTION_MOVE://滑动  
			nowX = event.getX();
			break;
		case MotionEvent.ACTION_DOWN://按下  
			if (event.getX() > bg_on.getWidth() || event.getY() > bg_on.getHeight())
				return false;
			onSlip = true;
			downX = event.getX();
			nowX = downX;
			break;
		case MotionEvent.ACTION_UP://松开  
			onSlip = false;
			boolean lastChoose = nowChoose;
			if (event.getX() >= (bg_on.getWidth() / 2))
				nowChoose = true;
			else
				nowChoose = false;
			if (isChgLsnOn && (lastChoose != nowChoose))//如果设置了监听器,就调用其方法.  
				changedLis.OnChanged(nowChoose);
			break;
		default:
			break;
		}
		invalidate();
		return true;
	}

	public void SetOnChangedListener(OnChangedListener l) {//设置监听器,当状态修改的时候  
		isChgLsnOn = true;
		changedLis = l;
	}

	public interface OnChangedListener {
		abstract void OnChanged(boolean checkState);
	}
}
